Stringed rackets in common usage for the various above-mentioned sports all have a head portion comprised of an elliptical, oval or circular frame and a matrix formed of a plurality of transverse and longitudinal strings, the latter being disposed along, and parallel to, the axis of the racket handle. The area of the matrix defined by the intersection of the longest transverse and longitudinal strings is known among racket sportsmen as the "sweet spot".
This "sweet spot" is so-called because it is the only area of the strings to produce the highest velocity and most certainty as to the flight path of a projectile (such as a tennis ball) when the projectile is hit by the racket; hence the area of greatest satisfaction.
Accordingly the prior art has attempted to provide a racket which is provided with means to make the hitting of the "sweet spot" easier as one practices. For example U.S. Pat. No. 3,545,756 to Nash teaches a racket head having string attachment rod sections of varying resiliency thereby enlarging the surface area of the "sweet spot". Another U.S. Pat. No. 4,076,239 to Hall uses a pair of flat plates secured on each side of the netting matrix in the area of the "sweet spot" which are adapted to make a distinctive sound when the projectile strikes them. This arrangement is thus an audible aid for the player. Yet another U.S. Pat. No. 4,151,549 issued to Hayes et al Feb. 27, 1979, disclosed a signal device which similarly makes a noise when struck.
With the exception of the first above-cited patent, the prior art teaches rackets which rely on ear-hand coordination for improved hitting on the "sweet spot". This might be confusing for some players more accustomed to visual-muscular coordination. A further disadvantage would be that such rackets could not be used by players who are hard of hearing or deaf.